12.0(20) on one router and 12.1(12) on the rest! Which 11.3 version are you running?
-Stefan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Diffy De Villiers Sent: Friday, January 18, 2002 4:04 AM To: [EMAIL PROTECTED] Subject: RE: URGENT - PLEASE HELP - OSPF summary route cost. [7:31832] Hi Stefan, Thank you for your input, but indeed things is more confusing now!!! I am glad to see that you got the expected results. Maybe the implementation differences lies in the version of IOS. I am using IOS 11.3 (what version are you using?). Kind Regards Diffy >>> "Stefan Dozier" 01/16/02 07:19PM >>> I hope I'm not confusing the issue here..... I plugged your config into my pod, with a few minor changes (interface types used). I used serials thorughout the net, where you used some ethernet interfaces, with the exception of RouterD where I used a loopback interface instead of the ethernet you used! Here's my config and RouterA's routing table. hostname RouterA ! interface Serial0 description connected to RouterB via network 1 ip address 192.168.1.2 255.255.255.0 ip ospf cost 1 ! router ospf 10 network 192.168.1.0 0.0.0.255 area 1 end ! hostname RouterB ! interface Serial0 description connected to RouterA via network 1 ip address 192.168.1.1 255.255.255.0 ip ospf cost 1 ! interface Serial1 description connected to RouterC via network 2 ip address 192.168.2.1 255.255.255.0 ip ospf cost 4 ! router ospf 10 network 192.168.1.0 0.0.0.255 area 1 network 192.168.2.0 0.0.0.255 area 0 end ! hostname RouterC ! interface Serial0 description connected to RouterB via network 2 ip address 192.168.2.2 255.255.255.0 ip ospf cost 4 ! interface Serial1 description connected to RouterD via network 3 ip address 192.168.3.1 255.255.255.0 ip ospf cost 64 ! router ospf 10 network 192.168.2.0 0.0.0.255 area 0 network 192.168.3.0 0.0.0.255 area 2 end ! hostname RouterD ! interface Loopback0 description network 4 ip address 192.168.4.1 255.255.255.0 ip ospf network point-to-point ip ospf cost 16 ! interface Serial0 description connected to RouterC via network 3 ip address 192.168.3.2 255.255.255.0 ip ospf cost 64 ! router ospf 10 network 192.168.3.0 0.0.0.255 area 2 network 192.168.4.0 0.0.0.255 area 2 end RouterA#sh ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default U - per-user static route, o - ODR Gateway of last resort is not set O IA 192.168.4.0/24 [110/85] via 192.168.1.1, 00:02:50, Serial0 C 192.168.1.0/24 is directly connected, Serial0 O IA 192.168.2.0/24 [110/5] via 192.168.1.1, 00:02:50, Serial0 O IA 192.168.3.0/24 [110/69] via 192.168.1.1, 00:02:50, Serial0 As you can see, I got the results expected! I am very curious why you're getting the results you posted, but I can't reconfig my pod right now to match your exact setup without sabotaging another issue I'm trying to resolve. Stefan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Diffy De Villiers Sent: Wednesday, January 16, 2002 9:23 AM To: [EMAIL PROTECTED] Subject: RE: URGENT - PLEASE HELP - OSPF summary route cost. [7:31832] Hi Andrew, Thank you for you willingness to assist. Someone in the group suggested that a routing loop may exists (i.e, the path Router A uses to get to network 3 is via B via C via D to network 3). Although this may explain the extra cost factor of 64, this is not what happens as can be seen from the following two traceroute outputs: RouterA>traceroute 192.168.3.1 Tracing the route to 192.168.3.1 1 192.168.1.1 4 msec 4 msec 4 msec 2 192.168.2.2 8 msec 8 msec * RouterA>traceroute 192.168.3.2 Tracing the route to 192.168.3.2 1 192.168.1.1 4 msec 4 msec 4 msec 2 192.168.2.2 8 msec 4 msec 4 msec 3 192.168.3.2 8 msec 8 msec * As you can see the optimal path is used everytime (i.e. Router A to B to C to network 3). When examining the Link-State Databases of the routers in Area 0, network 3 has a metric of 128 (and not 64 as would have been expected). Similarly network 1 has a cost of 2 (and not 1). Why is the costs of these two summary routes doubled?. Kind Regards Diffy de Villiers >>> "Andrew Larkins" 01/14/02 01:53PM >>> Hi, I am not to sure myself here. I will ask one of my colleagues here as well to see if he has any light that he can shed here. Regards Andrew -----Original Message----- From: Diffy De Villiers [mailto:[EMAIL PROTECTED]] Sent: 14 January 2002 13:01 PM To: [EMAIL PROTECTED] Subject: URGENT - PLEASE HELP - OSPF summary route cost. [7:31832] Hi Everybody This is the third time that I am posting this message to this studygroup, I had no reply to the previous two postings. Hopefully someone will be able to assist me this time. I have a problem understanding how costs are calculated for OSPF summary routes. To understand my problem refer to the following example: This is the internetwork diagram (with 4 routers A,B,C & D): netw 1 netw 2 netw 3 netw 4 [ A ]--------[ B ]--------[ C ]---------[ D ]---------| cost 1 cost 4 cost 64 cost 16 ---------------------------------- Here are my router configurations: ---------------------------------- hostname RouterA ! interface Serial0 description connected to RouterB via network 1 ip address 192.168.1.2 255.255.255.0 ip ospf cost 1 no fair-queue ! router ospf 10 network 192.168.1.0 0.0.0.255 area 1 -------------------------------------- hostname RouterB ! interface Ethernet0 description connected to RouterC via network 2 ip address 192.168.2.1 255.255.255.0 ip ospf cost 4 ! interface Serial0 description connected to RouterA via network 1 ip address 192.168.1.1 255.255.255.0 ip ospf cost 1 ! router ospf 10 network 192.168.1.0 0.0.0.255 area 1 network 192.168.2.0 0.0.0.255 area 0 -------------------------------------- hostname RouterC ! interface Ethernet0 description connected to RouterB via network 2 ip address 192.168.2.2 255.255.255.0 ip ospf cost 4 ! interface Serial0 description connected to RouterD via network 3 ip address 192.168.3.1 255.255.255.0 ip ospf cost 64 ! router ospf 10 network 192.168.2.0 0.0.0.255 area 0 network 192.168.3.0 0.0.0.255 area 2 -------------------------------------- hostname RouterD ! interface Ethernet0 description network 4 ip address 192.168.4.1 255.255.255.0 ip ospf cost 16 ! interface Serial0 description connected to RouterC via network 3 ip address 192.168.3.2 255.255.255.0 ip ospf cost 64 no fair-queue ! router ospf 10 network 192.168.3.0 0.0.0.255 area 2 network 192.168.4.0 0.0.0.255 area 2 -------------------------------------- If we do a "show ip route" at routerA we get the following output: RouterA>show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default U - per-user static route, o - ODR Gateway of last resort is not set C 192.168.1.0/24 is directly connected, Serial0 O IA 192.168.2.0/24 [110/5] via 192.168.1.1, 00:23:26, Serial0 O IA 192.168.3.0/24 [110/133] via 192.168.1.1, 00:18:51, Serial0 O IA 192.168.4.0/24 [110/85] via 192.168.1.1, 00:18:56, Serial0 Now for my problem: Looking at the diagram above, the metric from Router A to network 4 is 85. This is perfectly understandable (sumtotal of all the costs: 85 = 1+4+64+16). BUT NOW: The metric from RouterA to network 3 is 133!!! This is higher than the metric to network 4 even though we access network 4 via network 3. Logically I would have thought the cost to network 3 has to be 69 (64+4+1), not 133. Where does the cost-difference of 64 come from? The only rational explanation I have for this is that the ABR for area 2 added it, but why??? And why only add this cost factor for network 3 (and not for network 4)??? Please assist me if you know the answers since I cannot figure out a reasonable explanation. Thank you for your support. Abraham de Villiers Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=32454&t=31832 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
